Systemic lupus erythematosus biomarker and diagnostic kit thereof

Abstract

Disclosed are a systemic lupus erythematosus (SLE) biomarker and diagnostic kit thereof. The SLE biomarker is a segment within 1500 bp upstream from a transcription start site of a human IFI44L gene, namely chr1: 79,085,190-79,085,311 (hg19), and a DNA sequence thereof is represented by SEQ ID NO.1. The SLE diagnostic kit in the present invention comprises primers having sequences represented by SEQ ID NO.2 and SEQ ID NO.3, and a probe having a sequence represented by SEQ ID NO.4.

What is claimed is: 
     
         1 . A biomarker for early diagnosis of systemic lupus erythematosus, characterized by a segment of DNA sequence located in 1500 bp upstream region of IFI44L human gene transcriptional start site, wherein the segment of DNA sequence is located in chr1: 79,085,190-79,085,311 as shown in SEQ NO. 1. 
     
     
         2 . A use of a biomarker as defined in nucleic acid sequence represented by SEQ ID NO. 1 for the manufacture of SLE diagnostic kit, comprising detecting methylation levels of the SEQ ID NO. 1 sequence in 1500 bp upstream region of IFI44L gene transcriptional start site in blood from the subjects. 
     
     
         3 . The use of  claim 2 , comprising the following steps: (1) genome-wide DNA extraction in peripheral blood from the subjects; (2) measuring the concentration of the extracted genomic DNA; (3) treating the genomic DNA with bisulfite; (4) amplifying the DNA fragments represented by SEQ ID NO. 1 by the specific PCR primers; (5) examining PCR products by electrophoresis; (6) sequencing the PCR products; and (7) analyzing the results from sequencing and obtaining the methylation levels of two CG sites contained in SEQ ID No. 1. 
     
     
         4 . A set of oligonucleotide PCR primers, complementary to the nucleic acid sequence in the promoter region of IFI44L gene contained in SEQ ID No. 4 including the nucleic acid sequence in SEQ ID No. 1, wherein the set of nucleotide sequence of PCR primers in upstream primer is set forth in SEQ ID NO. 2 and in downstream primer is set forth in SEQ ID NO. 3. 
     
     
         5 . A SLE diagnostic kit, characterized in that the kit comprises a set of PCR primers is set forth in SEQ ID NO. 2 and SEQ ID NO. 3, and the downstream primer 5′-end is labeled with biotin. 
     
     
         6 . The SLE diagnostic kit of  claim 5 , wherein the kit further comprises a probe as defined in SEQ ID NO. 4. 
     
     
         7 . A probe for detecting the methylation levels of the nucleic acid sequence at CG sites in the promoter region of IFI44L gene as shown in SEQ ID No. 1, wherein a set of nucleotide sequence of the probe is set forth in SEQ ID No. 4.